1. Field of the Invention
The present invention relates to a conical nib and a writing instrument using the same. More particularly, the invention relates to a wear-resistant conical nib and a writing instrument using the same.
2. Description of the Related Art
A writing instrument which includes such a kind of conical nib is disclosed in Japanese Unexamined Patent Application, First Publication No. H9-156279. In the disclosed writing instrument, the nib includes a nib base body and a converging member. The nib base body includes a cylindrical base portion and five to eight combtooth-shaped pieces. The combtooth-shaped pieces, each having a circular arc cross section, protrude from one end of the base portion in a continuous manner. The combtooth-shaped pieces are arranged at equal intervals around the circumference of a shaft with slit-shaped grooves formed therebetween. A hemispherical split portion is formed at tips of the combtooth-shaped pieces. The converging member is formed by a metal pipe which may fit onto an outer periphery of the nib base body. When the converging member is fit onto the nib base body, the combtooth-shaped pieces are tapered gradually toward the tips thereof to form a conical shape. A hemispherical writing tip is formed at the tips of the combtooth-shaped pieces and ink feed paths are formed between adjacent combtooth-shaped pieces. An ink supply wick having a capillary action to an end tip thereof is inserted in a hollow space inside the nib (i.e., the pen nib base body). The ink supply wick is fixed to a tip of the pen shaft in an integrated manner and is connected to an ink reservoir inside the pen shaft. The thus-structured nib can be used in writing in many directions on a paper sheet. The nib can be used in writing from any positions and from any angles, even if the penis rotated about the pen shaft. In addition to that, characters of various features, such as characters of thick lines and thin lines, can be written by varying width of lines in accordance with writing pressure. Recently, the combtooth-shaped pieces have been made of an injection-molded plastic material in many cases in order to satisfy the demand for the improvement in machinability and in mass production.
However, writing instruments with such plastic conical nibs have a problem that wear resistance at the nibs is low and the nibs wear easily as compared with metal or ceramic ones.
The present invention is made to solve these related art problems and an object thereof is to provide a wear-resistant conical nib even if the conical nib is made of a plastic material, and to provide a writing instrument using the conical nib.